Color change on deprotonation of 5-(8,8-dicyanoheptafulven-3-yl)-2-hydroxy-1,3-xylyl-18-crown-5
Color change on deprotonation of 5-(8,8-dicyanoheptafulven-3-yl)-2-hydroxy-1,3-xylyl-18-crown-5
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5-(8,8-二氰基七富烯-3-基)-2-羟基-1,3-二甲苯基-18-冠-5去质子化时的颜色变化
DOI：
10.1016/s0143-7208(98)00003-5
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发表时间：
1998
影响因子：
4.5
通讯作者：
J. Mizuguchi
中科院分区：
文献类型：
--
作者：
K. Yumura;H. Otani;J. Mizuguchi
化合物5-（8，8-二氰基七富烯-3-基）-2-羟基-1，3-二甲苯基-18-冠-5是由8，8-二氰基七富烯和一个空腔中含有酚羟基的冠醚衍生的一种新型非苯型冠醚染料。对去质子化的颜色变化进行了紫外/可见光谱研究，特别注意金属选择性着色，使用各种碱金属碱。去质子化引起了显着的颜色变化，从红色到蓝色（λ max <$430 → 640 nm），但完全无关的阳离子物种的碱添加。此外，发现着色与无冠的8，8-二氰基七富烯取代苯酚的着色非常相似。有趣的是，通过MO计算的几何优化显示，冠醚环由于腔中氧原子的孤对排斥而严重变形，使得羟基直接暴露于周围环境。因此，标题化合物的电子态几乎与无冠化合物的电子态相当。这就解释了为什么没有阳离子依赖的着色发生，以及为什么红移位移主要是由于苯氧基（C2O −）的π电子离域进入七富烯发色团。
Compound 5-(8,8-dicyanoheptafulven-3-yl)-2-hydroxy-1,3-xylyl-18-crown-5 is a novel non-benzenoid crown ether dye derived from 8,8-dicyanoheptafulvene together with a crown ether having a phenolic hydroxide group in its cavity. The color change on deprotonation has been UV/Vis-spectroscopically investigated with special attention to the metal-selective coloration, using a variety of alkali metal bases. Deprotonation brought about a significant color change from red to blue (λmax≈430→640 nm), but quite irrespective of the cation species of base added. In addition, the coloration is found to be very similar to that of the uncrowned 8,8-dicyanoheptafulvene-substituted phenol. Interestingly, geometry optimization by MO calculations revealed that the crown ether ring is heavily deformed due to lone pair repulsion of the oxygen atoms in the cavity, making the hydroxide group directly exposed to the surrounding environment. Thus, the electronic state of the title compound is almost equivalent to that of the uncrowned compound. This explains why no cation-dependent coloration takes place and why the bathochromic displacement is mainly due to π-electron delocalization of the phenoxide (O−) into the heptafulvene chromophore.